CP4 Failure... WTH

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classic72

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May 22, 2019
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I purchased my '15 Duramax Denali HD 3 months ago with 95k miles. Sunday I was driving and the change filter message came on and I lost power... coasted into a fuel station. I had it towed to local dealer who tells me "fuel pump exploded sending metal shrapnel throughout the system.... going to cost $11k to fix").


I have done research in the last couple of hours telling me that it's common and I now see all the lawsuits. Any suggestions from others who have been through this?
 
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classic72

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May 22, 2019
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How difficult is the repair? I usually work on all our gassers... just not a diesel mechanic. Do you have to remove radiator, etc.?
 
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classic72

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I am in the Dallas/Fort Worth area. Doing the whole "warranty" lawsuits against GM about this rodeo with the dealer right now. I haven't gotten a solid answer.


Worst case, going to tow it if I can find a reputable diesel shop near or in Fort Worth or Dallas. Thinking I will do the CP3 conversion instead of going back with the CP4 (if GM won't pay for repair). The wierd thing is in his quote he didn't have injectors. He said it didn't make it into the engine... don't understand how either of those are possible if the rails are getting replaced.


What about the fuel tank... does it need to be dropped and drained?


Thanks for the replies.
 
036.6turbo

036.6turbo

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Jan 17, 2014
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classic72 said:
I am in the Dallas/Fort Worth area. Doing the whole "warranty" lawsuits against GM about this rodeo with the dealer right now. I haven't gotten a solid answer.


Worst case, going to tow it if I can find a reputable diesel shop near or in Fort Worth or Dallas. Thinking I will do the CP3 conversion instead of going back with the CP4 (if GM won't pay for repair). The wierd thing is in his quote he didn't have injectors. He said it didn't make it into the engine... don't understand how either of those are possible if the rails are getting replaced.


What about the fuel tank... does it need to be dropped and drained?


Thanks for the replies.
Click to expand...

Usually the complete fuel system is either cleaned or replaced, tank / lines / rails / injectors etc. Because the pump returns fuel to the tank constantly, once the CP4 eats itself, the metal ends up everywhere.

There have isolated cases of guys getting their insurance companies to cover the repairs, if you are out of your warranty window. (If you can prove you were sold bad fuel, pretty rare, but it supposedly has happened.)

If you stick with a CP4, at least install the exergy system saver on the new pump.

I converted mine to CP3.

Job is not too bad, just time consuming. Most conversion kits require the truck be deleted, because the CP3 and EGR stuff will not fit on the same motor. I guess there are a couple conversions that do not require it being deleted.
 
2004LB7

2004LB7

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I had a cp4.1 go bad on my 09 TDI. Sent metal into the rails, injectors, etc.

I didn't replace any of the plumbing, lines, rails or tanks. Just flushed them. Took the injectors apart and cleaned them up. Worked for two of the injectors but had to replace the other two. Luckily I already had a spare CP4 so the repairs didn't take too long.

If you end up doing the work yourself, drop the tank and clean it out along with the pickup. Flush the lines and rails with diesel and air. Then install that kit (Part # 12672028) mentioned by ikeG and Ne-max

Dont forgot and replace the fuel filter too with a good low micron rated one to catch any last remaining bits
 
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classic72

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Just an update... Dealer referred me to GM helpline, pretty adamant they would help and cover anywhere from 20% to 100% since I am so close to within warranty (at 103k). I called them and the call center person was not helpful and basically said no, but then escalated to a "GM Customer Experience Manager" who will take into consideration more than just the standard warranty.


I did find out that previous owner had extended warranty that expired at 100,020 miles *roll eyes*



I am not sure how it will go but I will keep the post updated for any in this situation in the future. I am sure its a case by case kinda thing with after warranty assistance.


In regards to the CP3 kit... I am also curious about the emissions and want the simplest installation with the most reliability. If that means removing emissions stuff I am cool with it if they consider me out of warranty. Everything hinges on how GM is going to treat me and this issue. I will say to any GM haters out there... these pumps are also on Powerstrokes so they are having the same problems too.
 
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classic72

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May 22, 2019
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As a sidenote, I recommend anyone who has experienced this problem to report it to the NHTSA. I just reported my incident and if enough continue to do it GM should issue a safety recall. Losing all power, including power steering and brakes while at highway speeds pulling a 20k pound loaded trailer is nothing to sneeze at. Fortunately I wasn't towing my usual load that day. GM lists it as a "hard start, no start" issue which is BS. These fuel pumps don't explode when the engine isn't running.

Here is the link to NHTSA:
https://www-odi.nhtsa.dot.gov/VehicleComplaint/
 
Bdsankey

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classic72 said:
Just an update... Dealer referred me to GM helpline, pretty adamant they would help and cover anywhere from 20% to 100% since I am so close to within warranty (at 103k). I called them and the call center person was not helpful and basically said no, but then escalated to a "GM Customer Experience Manager" who will take into consideration more than just the standard warranty.


I did find out that previous owner had extended warranty that expired at 100,020 miles *roll eyes*



I am not sure how it will go but I will keep the post updated for any in this situation in the future. I am sure its a case by case kinda thing with after warranty assistance.


In regards to the CP3 kit... I am also curious about the emissions and want the simplest installation with the most reliability. If that means removing emissions stuff I am cool with it if they consider me out of warranty. Everything hinges on how GM is going to treat me and this issue. I will say to any GM haters out there... these pumps are also on Powerstrokes so they are having the same problems too.
Click to expand...

The 6.7 powerstroke also has an electronic fuel supply pump. I don't know what the differences are but they are making more power than we can cp4 vs cp4.


I'm not huge on the 6.7 community but I don't think they are having the failure rates the duramax is. The duramax CP4 has to pull fuel from the tank just like an older CP3.
 
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